A great deal of effort has been expended in developing thickened aqueous hard surface cleaning materials. Various viscosity increasing systems, and thickened compositions or cleaning formulations have been attempted. Those skilled in this art recognize that there is a need for the successful production of thickened materials that can maintain an effective concentration of active cleaning materials on a target soil on a vertical or inclined surface for an extended period of time. When made, such thickened cleaners should contain cooperating ingredients that can remove soils that are resistant to conventional cleaners having a short residence time.
Thickened cleaner technology is embodied in a variety of disclosures including for example, Roggenkamp, U.S. Pat. No. 3,943,234, discloses acid liquid cleaners containing emollient thickeners. The emollients are commonly fatty alcohols, glycols or fatty esters. Stoddart, U.S. Pat. No. 4,576,728, teaches aqueous cleaning compositions having shear thinning behavior. The cleaners contain common surfactants and alkali metal hypochlorite bleaches in combination with an aromatic carboxylic acid component. Leifheit, U.S. Pat. No. 4,743,395, teaches thickened hydrochloric acid cleaners for hard surfaces such as porcelain, ceramic tile, etc. The cleaners use thickeners such as alkyl glycinates, alkoxylated tertiary amines, and other related organic thickener compositions. Rose et al., U.S. Pat. No. 4,770,814, teaches non-thixotropic shear stable aqueous cleaners that can be sprayed on hard surfaces. Smith, U.S. Pat. No. 4,900,467, teaches thickened aqueous compositions having viscoelastic properties useful as drain cleaner compositions. The viscosity is adjusted for chlorine control and to ensure that the material is denser than water to enable the cleaner to actively open clogged drains. Durbut et al., U.S. Pat. No. 4,919,839, which focuses on microemulsion liquid detergent materials using amine and other aqueous compositions. Neil et al., European Patent Application No. 314,232, teaches a liquid detergent composition for hard surface cleaning combining a blend of surfactants with other cleaning materials to obtain both acid and alkaline cleaning systems. Rorig et al., U.S. Pat. Nos. 4,842,771 and 4,853,146, teach compositions containing quaternary ammonium and tertiary amine oxide surfactants, organic anionic sulfonates and water. The combination of ingredients forms a thickened relatively thixotropic single phase cleaning material. Smith, U.S. Pat. Nos. 5,011,538 and 5,055,219, teach viscoelastic thickening compositions and methods of use containing quaternary ammonium compounds, organic counterions that can act as a hard surface cleaner. Stoddart et al., U.S. Pat. No. 4,783,283, teaches aqueous cleaning compositions displaying shear thinning behavior comprising alkyl amine oxides in combination with alkyl benzene sulfonate. Such compositions can contain alkali metal hypochlorite bleaches for hard surface cleaning. Messenger et al., U.S. Pat. No. 4,753,754, teaches lamellar phase liquid crystalline materials which are pourable at ambient temperatures. Such compositions contain a variety of anionic surfactants combined with a variety of other conventional cleaning materials.
Klewsaar, U.S. Pat. No. 4,888,119 discloses anionic/cationic surfactant complexes and their use in microemulsions for wash cycle fabric softening and Kern, U.S. Pat. No. 4,786,422 and Thomas, U.S. Pat. No. 4,929,367 describe such complexes, but in particulate wash cycle fabric softening additives. However, none of these patent applications describes or suggests applicants' preferred thickened systems or the diluted thick composition and none describes or suggests the unexpectedly beneficial removals of fatty soils resulting when such compositions are used, especially in dilute form. Carlton et al., European Patent Application No. 137,871, teaches a single phase viscous amine oxide anionic surfactant system containing an ionizable material providing an ionic strength to the cleaner of at least 3.5 moles/cm.sup.3.
British patent specification No. 2,190,681 and Loth, U.S. Pat. Nos. 5,076,954 and 5,108,643 disclose microemulsion cleaning compositions in concentrated and dilute forms, which comprise anionic synthetic organic surfactant, hydrocarbon solvent, cosurfactant and water, and which are intended for removing greasy soil from hard surfaces. Neil et al., European Patent Application No. 314,232, teaches and exemplifies thickened aqueous cleaners using a variety of surfactant cleaner materials with lower alcoholic (ethanol, isopropanol, etc.) solvents for hard surface cleaning. Non-thickened enzyme based cleaners are disclosed in Anderson et al., U.S. Pat. No. 4,421,664; Guilbert, U.S. Pat. No. 4,238,345, and others. Acid base cleaners are shown in Pikaar, U.S. Pat. No. 3,211,659; Casey, U.S. Pat. No. 4,587,030; Aszman et al., U.S. Pat. No. 4,501,680; and Norman et al., United Kingdom Patent Application No. 2,012,837. However, such prior art do not disclose the presence in such compositions of applicants' thickened systems or other complexes of anionic and cationic surfactants, glycol ether solvents and do not disclose the unexpectedly beneficial removal of fatty soils from both hard surfaces items and from laundry by microemulsions containing such complexes.
In the research and development of the thickened aqueous cleaners of the invention, we have noted a substantial failure of the prior art to produce an effective cleaning composition that combines low temperature cleaning efficacy with sufficient viscosity to maintain a substantial concentration of cleaning composition on partial or substantially vertical surfaces without draining substantial quantities of the ingredients from the soil. Further, a concentrate cleaning material that can thicken upon dilution and can contain cooperating ingredients that can penetrate, soften and promote removal of difficult soil has not been fully developed. A substantial need exists for thickened aqueous cleaners for the household, institutional and industrial food preparation environment.